The present invention relates to an apparatus for cutting wafer sandwiches or stacks of wafer sandwiches. More particularly this invention concerns such an apparatus which longitudinally and transversely cuts a wafer sandwich into a plurality of small rectangular pieces.
In the production of cream-filled wafer confections, a sheet of highly friable wafer is coated on its upper side with a heated sticky filling, termed xe2x80x9ccream,xe2x80x9d and then another such wafer is applied to it and the wafer sandwich thus formed is cooled to adhere the two wafer layers and cream filling together. When thus cooled the two wafers cannot be separated from the cream without destroying them.
Such a cream-filled sandwich is produced from relatively large wafer sheets measuring from 290 mmxc3x97460 mm to 350 mmxc3x97760 mm with a thickness of between 1 mm and 3 mm and a cream coating between 0.5 mm and 2 mm thick so that the resultant wafer sandwich measures between 3 mm and 20 mm thick, depending on how many cream layers are used. Obviously such a large item must be cut into small pieces for marketing. The small pieces can be sold as is or can be coated with chocolate.
The standard apparatus therefore normally stacks a plurality of such sandwiches atop one another into a wafer stack that it cuts into a group of strips that are then cut crosswise to subdivide them into a larger group of rectangular pieces. The outer edge strips are typically discarded because they are not of uniform dimensions and frequently the cream filling does not extend to the very edge. As mentioned, after cutting into rectangular pieces and discarding the irregular edges, the pieces are typically covered with chocolate or the like.
German patent document 3,732,269 of Pfister describes a wafer-sandwich cutter with two cutting stations spaced apart in a transport direction. The first cutter serves for longitudinally slicing with stationary blades spaced apart transversely of the transport direction. The second station has a plurality of blades spaced apart in the transport direction and movable transversely of the direction across the path of the wafer sandwich to cut the strips formed by the longitudinal cutter into pieces.
With this system a device upstream of the longitudinal cutter pushes the sandwiches through the two stations, with the upstream sandwiches bearing on the. downstream sandwiches and moving them and the longitudinal strips formed in the first cutting station pushing the pieces in the downstream second cutting station. The transverse cutter in the second downstream station is provided with a slide reciprocal longitudinally in the transport direction and serving to form gaps between succeeding wafer sandwiches. This longitudinal slide is in a downstream position when a group of longitudinal wafer-sandwich strips are pushed onto it, simultaneously pushing out the pieces cut in the preceding transverse-cutting operation. Once a group of longitudinal strips is positioned on the longitudinal slide in its downstream position, a hold-down plate is pressed down against the top surfaces of the strips and then the hold-down plate and the longitudinal slide are stepped back upstream, opposite the normal transport direction to form a gap between the downstream ends of the strips held between the plate and longitudinal slide and the upstream ends of the previously transversely cut strips. Once the longitudinal slide and plate, with the group of longitudinal strips clamped between them, is moved into an upstream position, the strips are cut transversely.
The transverse cutter is comprised of a transverse slide movable transversely to the direction underneath the longitudinal slide and carrying a plurality of upwardly pointed triangular blades that project upward through transverse slots in the longitudinal slide and into downwardly open transverse grooves in the hold-down plate. The transverse slide is shifted across and back to cut the longitudinal strips into pieces, with the downstream pieces falling off the downstream end of the longitudinal slide. Then the longitudinal slide is moved back to its downstream position, the hold-down plate is lifted, and the conveyor pushes a new batch of longitudinal strips onto the longitudinal slide, pushing the freshly cut pieces off the downstream end of the longitudinal slide onto an output table whence they travel to a further processing step.
The double-slide structure is fairly complex to manufacture and maintain, especially in a foodstuff-handling machine that must be maintained meticulously clean. The guides for the longitudinal movement of the longitudinal slide must be transversely, adjustable or pivotal about a vertical axis in order to set the movement direction of the slide parallel to the travel direction of the workpiece and to adjust the cutter transversely. The slides require that some space be left for longitudinal movements between the longitudinal cutter and the output station which is substantially longer than a standard workpiece. The output station must have a hold-down beam that holds the last row of wafer pieces pushed into the output station so they are not pulled back when the longitudinal slide moves back upstream. This hold-down beam prevents wafer pieces from sticking to the upstream workpiece and being pulled back upstream when the longitudinal slide and hold-down plate retract upstream to create the gap necessary to eliminate the scrap pieces to be cut from the downstream ends of the strips they are holding. Furthermore the entire hold-down plate and the frame holding it are fairly complex also so that they further add to the expense of the machine and the difficulties in maintaining it.
With the known machine the group of longitudinal strips clamped between the longitudinal slide and the hold-down plate is moved upstream and then downstream. Meanwhile the strips held between the longitudinal slide and the hold-down plate are vertically compacted somewhat. In the pause before the longitudinal slide moves back upstream, the hold-down plate and the hold-down beam must both be pressed down on the respective workpieces, whereupon the longitudinal slide is retracted and the transverse slide is moved back and forth to cut the strips clamped between the hold-down plate and the longitudinal slide into pieces. Subsequently the hold-down plate and longitudinal slide are moved back downstream, the hold-down plate and hold-down bar are both raised, and the conveyor must step a new workpiece through the longitudinal cutter and onto the longitudinal slide. These movements are complex and must be perfectly synchronized, further adding to the cost of manufacture. The lifter for the hold-down plate and the drive for the transverse slide are carried on the longitudinal slide, making the structure that has to be moved fairly massive so that the actuator for the longitudinal slide has to be relatively powerful and, of course, expensive.
Another disadvantage of the known machine is that it cannot be used on wafer sandwiches whose upper surfaces are covered with anything, such as cream, caramel, powdered sugar, or the like which would stick to or be damaged by contact with the hold-down plate. The machine can only be used with wafer sandwiches having a dry and relatively stable top surface.
It is therefore an object of the present invention to provide an improved apparatus for cutting wafer sandwiches or stacks of wafer sandwiches.
Another object is the provision of such an improved cutting apparatus which overcomes the above-given disadvantages, that is which is relatively simple, which can be manufactured and maintained at low cost, and that can be used with all types of wafer sandwiches, even those with a sticky or fragile upper surface.
An apparatus for cutting a wafer sandwich into a plurality of rectangular pieces has according to the invention a support surface defining a transport path extending longitudinally through a longitudinal-cutting station and a transverse-cutting station. A plurality of stationary and transversely spaced longitudinal blades extend across the path in the longitudinal-cutting station. The surface is formed in the transverse-cutting station with a plurality of transversely extending and longitudinally spaced slots. An abutment is displaceable immediately downstream of the transverse-cutting station between a blocking position in the path and a retracted position clear of the path. A plurality of transverse blades are displaceable transversely in the slots of the transverse-cutting station across the path. A conveyor above the surface has pusher elements engageable with the wafer sandwich for pushing it longitudinally in a transport direction along the path through the longitudinal-cutting station, into the transverse-cutting station and against the abutment in the blocking position thereof, and out of the transverse-cutting station in the retracted position of the abutment.
Thus with this system the workpiece, which can be a single wafer sandwich but which is normally a stack of wafer sandwiches, is engaged only on its lower surface by the support surface, on its trailing edge by the pusher elements, and on its leading edge by the abutment. The pusher elements set the sandwich or stack of sandwiches in position against the abutment so the transverse blades can cut it accurately into transverse strips. Thus rather than clamping the workpiece between an upper hold-down plate and the conveyor surface, the workpiece is engaged at its leading and trailing edges during the transverse cutting operation, and only at its trailing edge during the longitudinal cutting operation. Even if the upper surface of the workpiece is covered with a sticky cream coating, the machine will function perfectly since only the blades make minor contact with this upper surface. The transverse cutting takes place without moving the workpiece which greatly simplifies the system by eliminating the complex slide apparatus hitherto used. There can be as few as three transverse blades, or a much larger number depending on the size of the confection being produced.
The blades can be simple flat structures with sharpened front edges that form a large acute angle with the surface so as to press down the workpiece as it is being cut. Alternately rotatable circular cutting disks can be used for very fragile materials.
According to the invention the transverse-cutting station is upstream in the direction from the longitudinal-cutting station so that the wafer sandwich is cut into transverse strips in the transverse-cutting station and then the transverse strips are pushed by the elements through the longitudinal-cutting station and are cut therein by the longitudinal blades into rectangular pieces. The advantage of this is that the irregular leading and trailing edges can be trimmed off the workpiece in the transverse-cutting station so that the workpieces will abut each other squarely in a longitudinal row as they are pushed downstream through the longitudinal cutter. Of course some situations might require that the longitudinal cutter be upstream of the transverse cutter.
An actuator is connected in accordance with the invention to the transverse blades for raising them at one longitudinal side of the transverse-cutting station, displacing them while raised transversely across the transverse-cutting station in the slots, lowering them at an opposite longitudinal side of the transverse-cutting station, and returning them transversely below the surface to the one side of the transverse-cutting station. All the transverse-cutting blades can be mounted on a common beam or carriage extending longitudinally between a pair of endless belts or chains lying in vertical planes spaced longitudinally in the transport direction. As the blade-carrying carriage travels along the upper stretches of the endless conveyor elements they will project through the slots and cut, and when in the lower stretches they will be returned back to the starting side of the transverse-cutting station.
The actuator also carries separating fingers movable transversely across the transverse-cutting station while the transverse blades are returned transversely below the surface to the one side of the transverse-cutting station. Thus these separating fingers, which serve to strip off the leading and trailing edges of the wafer sandwich being cut, are only engaged with the workpiece once the transverse-cutting blades are clear of it. The separating fingers include an upstream finger at an upstream end of a wafer sandwich in the transverse-cutting station so that the upstream finger separates end scraps from the upstream end of the wafer sandwich in the transverse-cutting station. They also include a downstream finger at a downstream end of the wafer sandwich in the transverse-cutting station so that the downstream finger separates end scraps from the down stream end of the wafer sandwich in the transverse-cutting station.
In accordance with the invention in the retracted position the abutment is below the path and has a face forming part of the surface. Further a controller is provided for moving the conveyor elements step-wise synchronously with displacement of the transverse blades.